This disclosure relates generally to optical fibers, and more particularly to ferrules for multi-fiber optical connectors, along with optical connectors and cable assemblies including such ferrules, and methods relating to these components.
Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. In a telecommunications system that uses optical fibers, there are typically many locations where fiber optic cables that carry the optical fibers connect to equipment or other fiber optic cables. To conveniently provide these connections, optical connectors are often provided on the ends of fiber optic cables. The process of terminating individual optical fibers from a fiber optic cable is referred to as “connectorization.” Connectorization can be done in a factory, resulting in a “pre-connectorized” or “pre-terminated” fiber optic cable, or the field (e.g., using “field-installable” connectors).
Many different types of optical connectors exist. In environments that require high density interconnects and/or high bandwidth, such as datacenters, multi-fiber optical connectors are the most widely used. One example is the multi-fiber push on (MPO) connector, which incorporates a mechanical transfer (MT) ferrule and is standardized according to TIA-604-5 and IEC 61754-7. These connectors can achieve a very high density of optical fibers, which reduces the amount of hardware, space, and effort to establish a large number of interconnects.
Despite the widespread use of MPO connectors in datacenter environments, there are still challenges/issues to address. For example, although MPO connectors may contain any even number of fibers between 4 and 24 within the same physical package, 12-fiber connectors are the most commonly used. For some applications, such as parallel optics for 40 Gps Ethernet, only 8 active fibers are needed. Conversion modules may be used to convert the unused fibers from two or more MPO connectors into usable optical links (e.g., converting 4 unused fibers from each of two MPO connectors into 8 useable optical links), but the conversion adds costs to a network. Alternatively, cable assemblies can be built with only 8-fibers terminated by an MPO connector, but the MPO connector still resembles a 12-fiber connector. In other words, it can be difficult to see with the naked eye whether 8 fibers or 12 fibers are present. This uncertainty in fiber count may result in network issues if a connector with 12 active fibers is inadvertently mated to a connector with only 8 active fibers.
Additionally, securing the optical fibers in the ferrule of an MPO connector can be a challenge. An adhesive material is typically used for this purpose, with adhesive material being injected or otherwise supplied into an internal cavity of the ferrule. There must be sufficient adhesive material to ensure that the optical fibers are sufficiently bonded/secured to the ferrule. To avoid uncertainty on whether a sufficient amount of adhesive material is supplied, there may be a tendency to completely fill the internal cavity of the ferrule. Doing so, however, may increase the likelihood of the adhesive material being disposed on an exterior of the ferrule or otherwise exiting the ferrule, both of which may interfere with the normal operation of the ferrule as part of an optical connector.